Add TwilioVerifyExperimentEnrollmentManager

service/src/main/java/org/whispersystems/textsecuregcm/sms/TwilioVerifyExperimentEnrollmentManager.java

@@ -0,0 +1,74 @@
+package org.whispersystems.textsecuregcm.sms;
+
+import com.google.common.annotations.VisibleForTesting;
+import java.util.List;
+import java.util.Locale.LanguageRange;
+import java.util.Optional;
+import java.util.Set;
+import java.util.stream.Collectors;
+import org.whispersystems.textsecuregcm.configuration.VoiceVerificationConfiguration;
+import org.whispersystems.textsecuregcm.experiment.ExperimentEnrollmentManager;
+
+public class TwilioVerifyExperimentEnrollmentManager {
+
+  @VisibleForTesting
+  static final String EXPERIMENT_NAME = "twilio_verify_v1";
+
+  private final ExperimentEnrollmentManager experimentEnrollmentManager;
+
+  private static final Set<String> INELIGIBLE_CLIENTS = Set.of("android-ng", "android-2020-01");
+
+  private final Set<String> signalExclusiveVoiceVerificationLanguages;
+
+  public TwilioVerifyExperimentEnrollmentManager(final VoiceVerificationConfiguration voiceVerificationConfiguration,
+      final ExperimentEnrollmentManager experimentEnrollmentManager) {
+    this.experimentEnrollmentManager = experimentEnrollmentManager;
+
+    // Signal voice verification supports several languages that Verify does not. We want to honor
+    // clients that prioritize these languages, even if they would normally be enrolled in the experiment
+    signalExclusiveVoiceVerificationLanguages = voiceVerificationConfiguration.getLocales().stream()
+        .map(loc -> loc.split("-")[0])
+        .filter(language -> !TwilioVerifySender.TWILIO_VERIFY_LANGUAGES.contains(language))
+        .collect(Collectors.toSet());
+  }
+
+  @SuppressWarnings("OptionalUsedAsFieldOrParameterType")
+  public boolean isEnrolled(Optional<String> clientType, String number, List<LanguageRange> languageRanges,
+      String transport) {
+
+    final boolean clientEligible = clientType.map(client -> !INELIGIBLE_CLIENTS.contains(client))
+        .orElse(true);
+
+    final boolean languageEligible;
+
+    if ("sms".equals(transport)) {
+      // Signal only sends SMS in en, while Verify supports en + many other languages
+      languageEligible = true;
+    } else {
+
+      boolean clientPreferredLanguageOnlySupportedBySignal = false;
+
+      for (LanguageRange languageRange : languageRanges) {
+        final String language = languageRange.getRange().split("-")[0];
+
+        if (signalExclusiveVoiceVerificationLanguages.contains(language)) {
+          // Support is exclusive to Signal.
+          // Since this is the first match in the priority list, so let's break and honor it
+          clientPreferredLanguageOnlySupportedBySignal = true;
+          break;
+        }
+        if (TwilioVerifySender.TWILIO_VERIFY_LANGUAGES.contains(language)) {
+          // Twilio supports it, so we can stop looping
+          break;
+        }
+
+        // the language is supported by neither, so let's loop again
+      }
+
+      languageEligible = !clientPreferredLanguageOnlySupportedBySignal;
+    }
+    final boolean enrolled = experimentEnrollmentManager.isEnrolled(number, EXPERIMENT_NAME);
+
+    return clientEligible && languageEligible && enrolled;
+  }
+}